San Diego author Caitlin Rother wrote "Lost Girls," a book about Chelsea King and Amber Dubois and their killer John Albert Gardner, a convicted sex offender.
— K.C. Alfred

A “perfect storm” of factors — nature and nurture — helped turn John Gardner into the sexual predator who killed North County teens Amber Dubois and Chelsea King, according to a provocative new book about him that has riled his victims’ families.

In “Lost Girls,” due out Tuesday, veteran San Diego journalist and true-crime author Caitlin Rother offers the longest look yet at Gardner — his dysfunctional family, his mental illnesses and addictions, his hair-trigger violence.

It chronicles the opportunities authorities missed to corral him.

The book relies heavily on dozens of interviews Rother did with Gardner’s mother, the previously silent Cathy Osborn; with other relatives and friends; and with Gardner himself, who is serving a life sentence at Corcoran State Prison.

Although the arc of the story will be familiar to San Diegans, the book provides new details, some of them lurid, and behind-the-scenes accounts.

How Gardner shared homicidal fantasies with prison therapists years before the murders. How he tried unsuccessfully to check himself into a mental hospital weeks before Chelsea was killed. How Chelsea fought back, hitting him with a stick.

Rother said her hope is that society can benefit from knowing what makes someone like Gardner tick, and maybe prevent other slayings.

“I’m not doing this to sensationalize what he did, or glorify what he did, or excuse what he did, or rationalize what he did,” Rother said. “I’m trying to explain so that we can learn from it, because if you turn a blind eye to something like this, nothing’s going to change.”

Amber, 14, was abducted at knifepoint while walking to school in Escondido in February 2009. Chelsea, 17, was ambushed while running at Rancho Bernardo Community Park a year later. The book is dedicated to them, but in a way, they’re missing from the story: Their families wouldn’t participate in the project.

“To write a book that gives the coward or his family a platform to seek an ounce of pity for destroying my family is disgusting,” Brent King, Chelsea’s father, said in an email. “His family sat silent in their home for five days while helicopters circled the park behind their yard, searching for our daughter. Now Ms. Rother chooses to profit off our re-victimization. Our community has had enough pain. Our family has had enough pain.”

Carrie McGonigle, Amber’s mother, said she, too, feels re-victimized and has no plans to read the book. “I just hope it’s about what a monster Gardner is,” she said.

A troubled childhood

Rother, 49, spent almost 20 years working for newspapers, 13 with the U-T. She’s written five other true-crime books, including “Poisoned Love,” about Kristin Rossum, a county toxicologist convicted of killing her husband and staging it to look like a suicide.

Long interested in abnormal psychology — for a while she wanted to be a therapist — Rother said she finds sensational murders fascinating, and believes if the stories are told right, they can be educational and inspirational.

She said she was moved to write “Lost Girls” after watching the impact the Gardner case had on the county — first the outpouring of “love and hope and goodwill” as people searched for Chelsea, and then the “groundswell of anger” directed at Gardner.